<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="https://cdn.jsdelivr.net/npm/vue@2.5.17/dist/vue.js"></script>
</head>

<body>
    <div id="app">
        <strong>{{msg}}</strong>
        <button @click="click">按钮</button>
    </div>
</body>
<script>
    const app = new Vue({
        el: "#app",
        data: {
            msg: "我叫贺俊杰!"
        },
        methods: {
            click() {
                this.modifyMsg()
            },
            modifyMsg() {
                this.msg = "hello! " + this.msg;
            }
        }
    })
</script>

</html>